1. Field of the Invention
The present invention relates to a method and an apparatus for manufacturing chain-like food products such as sausages or the like by using natural intestines.
2. Description of the Related Art
Conventional chain-like sausage products are manufactured by stuffing an animal's gut, that is, a natural intestine such as a sheep's gut or a hog's gut, or an artificial casing such as a cellulose casing or a collagen casing, with a stuffing material.
In this case, there are frequent occasions when the manufacturing method and apparatus differ between the case in which a natural intestine is used as the casing and the case in which an artificial casing is used.
Namely, since the natural intestine is liable to be broken when it is stuffed with the stuffing material or when the stuffed natural intestine is linked, the method and the apparatus using the natural intestine are difficult to put to practical use unless various measures are provided.
Such a problem becomes more conspicuous in the case of a so-called high-speed stuffing apparatus in which the natural intestine is stuffed with a stuffing material and is pinched.
Apparatuses for manufacturing chain-like natural-intestine sausages, which are each comprised of an endless conveyor provided with pinchers at predetermined intervals as well as a rotating stuffing nozzle, are publicly known through Japanese Patent Application Laid-Open Nos. 49-101577 and 50-91489 (No. 50-91489 corresponds to U.S. Pat. No. 3,873,744.
In these known manufacturing apparatuses, the natural intestine fitted over the stuffing nozzle is rotated together with the rotating stuffing nozzle by increasing a frictional force acting in the rotating direction between the rotating stuffing nozzle and the natural intestine.
However, in these conventional techniques, since the natural intestine is locally engaged with the rotating stuffing nozzle or a fin head attached to a vicinity of a distal end of the rotating stuffing nozzle, there are cases where slippage occurs between the natural intestine and the rotating stuffing nozzle or fin head. Further, since the force from the rotating stuffing nozzle or the fin head is concentrated on parts of the natural intestine, breakage of the natural intestine is liable to occur when the intestine is pulled out from the rotating stuffing nozzle or the fin head.
In addition, in the manufacture of natural-intestine sausages, the membrane of the natural intestine is thin and very soft, and does not have a high shape-retaining property, and the rigidity of the stuffed natural intestine which is stuffed with the sausage material is small, with the result that a twist is liable to occur in the stuffed natural intestine at positions other than those where the stuffed natural intestine is pinched. In Japanese Patent Application Laid-Open No. 49-101571, an arrangement is provided such that after tie stuffed natural intestine is pinched by the pinchers, tie stuffing nozzle is rotated so as to allow a twist to be reliably produced at the pinched portion. In this case, since the stuffing nozzle rotates intermittently, and the stuffing nozzle is stopped except during the step of pinching by the pinchers, the problem that the position of a twist produced in the stuffed natural intestine is not fixed is unlikely to occur. However, since the stuffing nozzle is rotated intermittently, the rotation of the stuffing nozzle is sometimes difficult to be imparted to the natural intestine over the stuffing nozzle, so that there is the risk that a required number of twists cannot be imparted to the pinched portion. Furthermore, there are additional drawbacks in that the intermittently rotating-type stuffing nozzle, which rotates at high speed, is liable to undergo run out in the rotation of the stuffing nozzle, and lacks the durability of the apparatus.
In the sausage manufacturing apparatus disclosed in Japanese Patent Application Laid-Open No. 50-91489, a fin head, which has a hollow cylindrical portion and fins provided in such a manner as to project radially from an outer periphery of the hollow cylindrical portion, is detachably provided on the stuffing nozzle. Since the fin head expands the diameter of the natural intestine stretched from the inner side thereof, and is discontinuously and locally engaged with the stretched intestine, the twisting rigidity of the natural intestine is very low. For this reason, the rotation of the fin head is difficult to be imparted to the stuffed natural intestine portion via the stretched natural intestine portion. Since the stuffing nozzle rotates continuously, a twist can possibly occur not at the portion pinched by the pinchers but at a position located in front of and in proximity to a discharge end of the fin head.
Further, since this fin head is larger than the inside diameter of the natural intestine, when the natural intestine is fitted over the stuffing nozzle, the fin head must be removed from the stuffing nozzle, which is very inferior in the operating efficiency. In addition to it, as these prior arts are aimed at using either natural intestines or artificial casings, the technical subject is yet to be solved as to how to have the same stuffed diameter while using natural intestines with nonuniform diameter.